Something in the water
by nipponophile
Summary: Donna is not feeling like herself. Or is she finally feeling that way?
1. Chapter 1

_**Disclaimer: The fact that this little interlude never made it into Season 4 proves that I don't own the Doctor nor Donna in any way, shape or form.**_

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><p><strong>Something in the water<strong>

Donna _had_ been feeling confident. Nah, that didn't quite capture it. What felt more confident than confident? Because that was how she had felt _then_.

_Ah, that's the word. Smug. _

She _had_ been feeling smug.

Because she _had_ thought that she had finally put herself in a situation where she was going to emerge the winner, victorious in a battle of wits with an alien whose enormous brain overshadowed hers in every way and yet who inexplicably had allowed himself to be manipulated into a bet Donna had proposed believing without a shadow of a doubt she would win.

For she had bet the Time Lord that he wouldn't be able to persuade her to 'mate' with him.

Of course, she trusted him not to take undue advantage of his Time-Lordy alien-ness and everything that entailed, but to keep things fair – _well, as fair as things could be between a Time Lord and a human - _she felt she had had to establish some ground rules as well. No perception filters. No hypnotism or their intergalactic equivalents. And none of that wibbly-wobbly, timey-wimey….'stuff'.

With those rules spelt out, and she had thought she had it in the bag. Because she knew her own mind. Her own heart.

At least she thought she had. Thus the smugness.

Right _now_, however, all she felt was hot, bothered and more than a little bewildered, the doubts multiplying like transponding Adipose as she found herself for probably the tenth time that hour heading into the bathroom to give herself another blast of cold water. While she bit her tongue. And dug her fingernails into her palms, her arms, the backs of her legs. Hard.

Anything to stop the yearning, the ache. For she was literally _aching_ for him.

If she hadn't known the Doctor like did, she might have suspected foul play, the Doctor doing something sneaky or underhand just to be able to win and not suffer the immeasurable blow to his mighty Gallifreyan ego in having to admit Donna was right.

But as she lay back on the bed, her feet pawing and pushing against the sheets like some kind of crazed cat in heat, she had to admit to herself that the Doctor wasn't like that. He wouldn't do something like that. _Especially_ not just to win a bet.

So why was she feeling like this? Like she would ignite if he so much as looked in her direction? Like she had to have his lips on every part of her at the same time otherwise she might go insane with desire? Like she wanted to crawl inside his skin even as she yearned for him inside her, filling her to overflowing?

Donna had never, _ever _experienced need this intense and initially it had scared her so much that she had had to beg off the Doctor's company in a sudden rush with some pathetic excuse about festival food that appeared to have gone down the wrong way and lock herself in her room where she could climb the walls _in private._

Although, in all seriousness, she didn't know how successful that strategy was going to be. She couldn't explain what had come over her or, more importantly, how to stop it. At the moment, it seemed to only grow stronger rather than dissipate, and if things didn't change pretty soon, she knew she wouldn't be able to restrain herself any longer. She'd bust down her door, and his, and any others the TARDIS might erect, to get to her Doctor, strip them both naked, and have her wicked way with him.

She rolled over onto her stomach, her groans muffled by the pillow she held in a death grip as she ground herself against the mattress.

_What is WRONG with me?_

Only an hour before everything had been the picture of normality as he had whisked her off to all the places he had promised to take her when he had thought she was leaving him for good – _As if! I would never leave him, couldn't if I tried, especially NOW - _and, with his cool hand wrapped around hers, she had marvelled at the fifteenth Broken Moon of the Medusa Cascade, thrilled at the Lightning Skies of Cotter Palluni's World and gazed enraptured at the Diamond Coral Reefs of Kataa Flo Ko.

It was his way of trying to impress her, dare she say it, _woo _her, and he had done, not that she'd _ever_ admit to it - perhaps even under pain of death - a rather brilliant job of it.

It had been extraordinarily difficult to maintain her resolve after such a showing, especially when the Doctor had turned to her as they bobbed gently in a boat atop the glistening reefs, and flashed her one of those smiles, more dazzling and brilliant than even the Kataa Flo Ko diamonds, the one that simultaneously said See, I told you it would be spectacular, and Go on, admit it, you're impressed and _I know you can't resist me when I smile like this. _

Wait, his smile had never said _that_ to her before.

Nevertheless, she had held firm, gently dismissive of his tempting invitation to succumb to the charms of the intergalactic enticements he had dangled in front of her, and managed to return to the TARDIS very much in control of her emotions and her actions.

Or so she had thought.

They had barely sat down at the kitchen table for a cup of tea and a biscuit when she felt something stirring in the very depths of her, stirrings she somehow knew were being caused by _him_.

Not even his presence but just the mere _thought _of him, for when she squeezed her eyes shut so as to block out the suddenly maddeningly alluring sight of his rumpled suit and even more rumpled bed-hair not to mention the chocolate come-hither eyes, it did absolutely squat to ramp down her hormones that were progressing from their previously recumbent state through a brisk canter to an out-of-control gallop. She had had to physically remove herself from his proximity before she found herself doing something that would have embarrassed them both and likely got her deposited back in Chiswick quicker than the Doctor could demolish a packet of jelly babies.

_When will this torture end?_

No doubt the Doctor would be curious, perhaps even worried by this stage, at her strange behaviour but the way she was feeling right now, she just couldn't risk being in the same room with him. She had doubts that it was safe even to be in the same TARDIS as him.

Of course, the Doctor chose that precise moment to knock on her door.

"Donna? Are you alright? Did something upset you?"

She could hear the concern and…something else…in his voice.

"I'm fine, just a bit of a tummy bug" she managed to call out in a rather unconvincing tone.

"Donna, we didn't eat anything while we were out, let me take you to the med bay, make sure nothing's…."

"I'm fine!" she interrupted, sitting up quickly, "really, please don't fuss, I just need some rest…"

Too late, the door slid open and the Doctor entered the room, walked two steps towards her, stopped and just _stared._

Only now did Donna look down at herself and realise the state she was in – damp hair curling loosely around her face and over her shoulders, half-moon indentations on the skin of her arms and legs, wet - _and now completely transparent!-_ nightie clinging scandalously close to her every curve and revealing rather accurately the level of her current – _ahem – _agitation.

The Doctor said nothing for a beat, his mouth instead gaping slightly like a fish out of water before finally collecting his wits and rushing over to her in a mild panic, completely ignoring her wildly gesticulating hands urging him to get away.

He moved swiftly to sit beside her on the bed, one hand gently grasping her forearm, and the other feeling her forehead.

"Your temperature does seem a little bit elevated, do you have any other symptoms, cold chills, aching limbs, sore eyes…"

Donna could barely hear what he said, instead her ears were filled with the sound of her own heartbeat that had escalated once again to the point she thought the organ might spontaneously burst out of her chest. His indescribable, unmistakeably masculine scent assaulted her nostrils, his body was so close the hairs on her arms and legs were literally standing on end as if even they yearned for him, her breathing became more erratic.

Before he had the chance to say another word, her other hand shot out, grabbed him roughly by the back of the neck and pulled him to her, him barely being able to eke out a squeak of surprise before her lips crashed into his and her tongue, roughly insistent, pried his mouth open so that she could explore properly.

It was some seconds before he appeared to overcome his shock but to _her_ astonishment, instead of pulling away, he sank into her embrace and she felt the tension in his body melt away as he gave himself fully to the kiss, his tongue dancing into life and meeting hers with equal ardour. She lay back on the bed, pulling him on top of her and wrapping her long, wet legs around him, pleased to find that he seemed just as eager for her as she was for him.

"Oh Donna, I have waited so long for this" he murmured in her ear even as his tongue traced its curves in a slow, seductive arc.

"Doctor, I don't know what you did" she gasped out, "but it worked and you were right and can we just ….ooooohhhhhh". He had moved his mouth to her neck, momentarily disrupting all coherent speech.

"I didn't do anything, really, except take you to all those places," he mumbled against her skin, "obviously, they had a much more persuasive effect on you than I ever could."

"Something in the air, maybe, then. 'Cause we didn't eat the food or drink the water…."

She stopped and kissed him even more deeply and passionately not really caring anymore about the why, and instead focussing on how she could feel, taste and explore more of him.

At which point, the Doctor pulled away abruptly, sat up and smacked his forehead loudly in an exaggerated gesture of revelation.

"Of course! Why didn't I realise that? Donna, ever the brilliant one!"

Her head reeling not only from the mind-blowingness of his kisses but even more from the sudden deprivation of them, Donna sat up as well and fixed him with what she hoped was a steely, demanding glare but feared would come up more like slightly clueless determination given her current aroused state.

"What" she stammered "are you talking about?"

"The diamond coral reefs of Kataa Flo Ko, one of the top ten most beautiful sites in all the universe…"

"Yes, yes, you can dispense with the travel brochure speak" she said testily, her glare nevertheless softening as it was irresistibly drawn back to his lips.

He paused at her tone and rubbed the back of his neck nervously, a gesture he only ever did when he was about to say something he feared would arouse her ire.

"Well, you see, normally viewing the reefs is just that, looking at all the sparkly stuff, and marvelling at the loveliness…"

"Get to the point, Spaceman. Fast."

"Right then, well, every so often, well, not so often really, in fact, quite rare actually, only once in a millennium which would explain why I'd forgotten about seeing as I wasn't even around the last time it happened…"

"DOCTOR!"

"Okay, well once in a millennium as a kind of diamond diamond diamond-ey jubilee, kind of like what the Queen is having this year but with a lot more diamonds, anyway…on this special anniversary, at this very significant stage of the coral's life cycle, it releases a special hormone into the water kind of like a…

"Let me guess, love potion…" Donna interrupted, rolling her eyes in a gesture of _why-does-this-not-surprise-me_.

"Ah, yes….a love potion…" the Doctor sputtered on, only occasionally daring to look Donna fully in the eye, "…that is designed to ensure the complete and healthy renewal of the reef for another millennium."

He paused, throwing Donna a guilty gland before casting his eyes downward again, somewhere around the region of his right knee. "But which also has a rather powerful aphrodisiac effect on whoever or whatever touches the water at the time." He stopped and looked up at her sheepishly.

"A rather important fact you neglected to tell me" Donna snipped angrily as she recalled trailing her fingertips in the glittering waters, spellbound at the beauty and luxuriating in the Doctor's rapt and undivided attention. Which had probably been the reason behind his forgetfulness.

"I would have told you, but it kind of got lost, what with all the trying to impress you and prove you wrong and win the bet. I'm so sorry Donna." He looked down again, ashamed, and moved himself a little further away from her.

"Just tell me how long I'm going to feel like I have to shag you or I'll die."

"The effects wear off after about a week."

"A WEEK?" Donna roared, causing the Doctor to skip back further on the bead, almost careening off the side.

"If it helps, I'll have the TARDIS move our rooms far apart temporarily so that there's less chance of us running into each other." He offered rather weakly.

"Don't know if that's gonna work. Angry as I am with you, and as much as it _kills_ me to admit this, the way I feel right now, I would rip through this ship with my bare hands just to be able to get to you and kiss you again."

She looked up briefly, imploringly, at the TARDIS. _Sorry._

At the same time, she was both gratified and mortified to see the Doctor blush scarlet at her emphatic expression of determination, even as he was obviously, desperately trying to suppress a smirk.

Despite her earlier outburst, however, he was clearly feeling comfortable (and brave) enough to approach her again, inching his way back over the covers towards her.

"No need for that," he said softly, his eyes holding hers with sincerity and smoulder in equal measure, "I'll kiss you anytime you like."

"Right now, that is an extremely enticing and dangerous offer." Donna said, slowly leaning in towards him.

She heard his breath catch as she stopped, her lips a hair's breadth from his and turned her sultry-lashed gaze up to him.

"There is of course one other possibility," she said, her voice low and sexy.

"And that is?" the Doctor had stopped breathing almost completely now.

"We could just let the hormones do their work."

She saw his hearts skip a beat as his mind processed that suggestion.

"Then that would be them kissing me, not you," he said, his words measured, deliberate and holding a faintly detectable heaviness. "When I finally win that bet, because you never put a time limit on it and I am not going to give up, _you_ will be the one seeking the kissing. And the mating." He gave her a cheeky wink, earning an _Oi!_ and a slap, albeit a soft one.

"Because you want to. Because you love me as much as I love you."

And before she could even react to THAT bombshell he was gone, leaving her to ponder his words and deal with her frustration as the hormones continued to rage and the taste of him lingered on her lips.


	2. Chapter 2

_**Disclaimer: That the characters aren't mine should be obvious given that this completely canon-compatible episode, sadly, did not appear in the series.**_

**Something in the water – Chapter 2**

He leant on the wall next to the door just closed behind him, hearts pounding, head tilted back, eyes closed. His hands gripped the inside of his ship as if to stop himself from crumbling to the floor. The TARDIS, feeling her Master's turmoil, tried her best to calm him, blowing a cooling breeze on his rapidly overheating body that wanted nothing more than to collapse into a miserable heap.

It had taking every ounce of his strength to say no to Donna just then, to turn and walk away and leave her, when all he really wanted to do was give in to her hormones – and, if he were honest, his – and take things to their natural conclusion.

Damn his principles and integrity and all those other pesky do-the-right-thing feelings.

_Why do I think I have to win the bet fair and square anyway? A win is a win! Who cares how I got there? The fact was I was there! _Right_ there. I had her in the palm of my hand…or was that other way around?..._He shook his head at the graphic and tantalising but right now rather unhelpful mental image_, She _wanted _me and I was THAT far from…_

He sighed, lowered his head and pinched the bridge of his nose in frustration. He had wanted her, too. He had wanted her so much it physically _hurt._ And the things he had wanted to do to her, with her, were at the very least somewhat indecent. He suspected in some galaxies they were even illegal.

And of _course_ it had been at that precise moment that he had suddenly decided to hop up on his moral high horse and gallop right out of there. Leaving his best friend, his GORGEOUS and extremely aroused best friend, all alone and probably mad as hell at him. For which he couldn't really fault her. After all, that would have been how he'd have felt in her position.

Except that he wouldn't have, because, thanks to his superior Time Lord physiology, he wasn't affected in the slightest by skin-absorbed hormones. Not that he'd even dangled so much as fingertip in the water, mind. _Not sure why. Must have been some subconscious Gallifreyan spidey-sense type of thing._

In any case, the upshot of yet another pleasure-trip-gone-wrong was an intensely sexually frustrated companion, a disappointed and toey Time Lord and the exceedingly gloomy prospect of an entire week without even seeing or talking to his Earthgirl, much less even getting remotely close to shagging her.

A twinge in his nether regions at that latter thought had him deciding that now was a very good time for a cold shower, and with grim determination he headed back to his room. Which, he noted with a slightly annoyed upwards glare, was still _right next to Donna's. _ _Not helping. _He hoped the TARDIS had picked up on his ticked-off state and would make the necessary adjustments before he got out of the shower.

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><p>No such luck. On either count, actually. In spite of a good 30 minutes of blasting artic-temperature water he was still stubbornly standing to attention. And a quick peek out his bedroom door revealed it to be still sitting uncomfortably adjacent to that of his probably close-to-murderously-enraged-by-now best friend's.<p>

He flung his still slightly damp and goose-fleshed body onto the bed, the bounce of the mattress quickly dampening under his heavy despondency.

He shouldn't have forgotten to tell her. He shouldn't have gotten so distracted, gazing at her out in the boat. He shouldn't have kissed her like that in her bedroom just then. He _definitely shouldn't _have let her pull him down on top of her.

_But how could I have _not?

Now, of course, it was all too late, nothing but spilt milk, and he'd left Donna to clean up the mess.

But he just couldn't go back in there and take advantage of her, could he?

_Could he?_

_That would just be all kinds of …. wrong._

_But it would _feel _so RIGHT._

It occurred to him just then that his thought processes, usually so ordered and logical, were starting to unravel, tying him up in knots.

He couldn't stop thinking about her. About their kiss. About her taste. How she smelled. How she felt. How she felt under him. How she'd feel around him. Surrounding him.

He suddenly felt hot and a rush of blood, and he rolled over on the bed with a deep groan and then a sudden, sharp yelp as he rolled on _it._

Obviously, another _exceedingly_ cold shower was required. Immediately.

What was wrong with him? He'd never had this much trouble ramping down his emotional and biological reactions. Not even in response to Donna.

_Not that she isn't the sexiest, most beautiful woman in the entire cosmos and I would do just about _anything_ to be back in her bed and her arms and _her_ right now, and…._

_STOP IT!_

He rolled over onto his back again, slightly spread eagled, and rubbed his hands over his face.

Yes, he found Donna attractive and yes he did love her, deeply. But he had never felt so out of control like this, and his grip on self-restraint was becoming more tenuous by the second. That was not normal. Something else was going on here.

He needed to find out what, fast.

Motivated by the prospect of identifying a rational, scientific explanation for his….well, there were no other words for it, really…extreme horniness, he sprang to his feet and, clad in nothing but the bath towel wrapped firmly (he hoped) around his waist, he dashed out of his bedroom and down to the medical bay, not even daring to turn his head in the direction of her bedroom as he passed.

_I'm going to get to the bottom of this. Because even if Donna manages to survive the next week, I know I can't._

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><p>Some minutes later, his glum mood had turned even gloomier, shoulders slumped in a posture of defeat as he regarded the information on the screen in front of him, that seemed to mock his supposed intelligence even as it cheerily informed him that Time Lords were most certainly not immune to the hormonal charged waters of Kataa Flo Ko. Quite the contrary actually, they were even more susceptible to its powers than most other species, and it didn't even require direct contact with the waters themselves. All it took was the exchange of bodily fluids with someone who <em>had<em> touched the water.

Exchange of bodily fluids like, for example, kissing. Someone who had touched the water like, for example, Donna.

And his present incarnation, not one to do anything by halves, had not just kissed her.

Oh no, he had tried to snog her senseless. Taste her tonsils with his tongue.

_Enough bodily fluid exchange there to get a bull elephant excited, never mind one too-skinny-for-words Time Lord._

This was bad. This was _very_ bad.

He could sense that the TARDIS knew it too. Her low, steady hum he knew was supposed to sound menacing, but he detected the nervousness underneath, the orange lights meant to emphasise her resoluteness undermined by an intermittent wavering she couldn't conceal.

_Almost feel sorry for her, _ he thought as the flickering lights reflected on his rapidly darkening countenance, _she's really got her work cut out for her._

For his mournful despair at whether he would be able to hold himself back was fading rapidly, replaced by a growing sense that he didn't really want to fight this, damn the consequences. Even if they included destroying his relationship with his red-haired companion.

He could feel the hormones coursing more and more powerfully through his veins, completing his transformation from morbid resignation to twisted triumphalism. The TARDIS would fail. Oh, she could _try _stopping him, but it wouldn't work.

Because he knew Donna wouldn't.

He looked up then, with a wicked, lustful gleam, prompting the TARDIS to stutter out a series of more frantic whistles and beeps, almost as if to say: _Don't do this. _

Ignoring her, he got to his feet, stance menacing, and turned his eyes towards Donna's bedroom door.

_Game on._


End file.
